Decorate with endless spices (3)
I believe the answer is:
ice
'decorate' is the definition.
(to ice a cake is to decorate it)
'with endless spices' is the wordplay.
'with' indicates the answer is hidden within the clue.
'ICE' can be found hidden inside 'endless spices'.
(Other definitions for ice that I've seen before include "Skating surface" , "Cold stuff used in enticement" , "Top cake" , "Reserve" , "Decorate with frosting" .)